The invention relates to a process for attaching a functional element to a flat material and a connection between a functional element and a flat material.
Processes for attaching or fixing functional elements, especially of connecting elements such as nuts, bolts or the like to a flat material, for example to a workpiece which has been produced from a flat material, are known in the most varied versions.
Processes for attaching or fixing functional elements and connecting elements such as nuts, bolts or similar connecting elements to a flat material or a workpiece which has been produced from this material are known in different versions. Thus, in particular a process is also known in which the connection or fixing of the respective functional element takes place by riveting in the region of a dome-like section which has been produced from the flat material by permanent or plastic deformation, i.e. by drawing or pressing (EP 539 793 B1). In this known process, after joining and during riveting of the rivet collar provided on the functional element the dome-like section is deformed back such that the diameter of the joining openings in the flat material is reduced and thus its edge is pressed against the rivet collar to produce a radial compressive annular strain, to achieve additional anchoring. This process requires a relatively complex tool. Furthermore it has been shown that against expectations with this process a significant improvement of anchoring and resistance of the functional element to being torn out in the workpiece and in the flat material is not achieved.
It is an object of the invention to devise a process which can be carried out with simplified means and which still enables anchoring of functional elements in a flat material with high resistance to tearing out.